The invention relates to phytosanitary formulations.
Phytosanitary formulations are widely used in agriculture and horticulture.
Phytosanitary formulations comprise an active ingredient which has an activity on the production of plants, such as compounds having fertilizer, herbicide, fungicide, pesticide or insecticide activities, and a carrier which may be liquid or solid.
Generally, phytosanitary formulations are spread under the form of a solution on the plant or on the soil in which a plant grows. But they can also be under a solid form as powders or particles which, when contacted with water, spread the active ingredient on the soil or (on) the plant.
However, phytosanitary formulations, and more precisely the active ingredient thereof, undergo degradation reactions when exposed to sunlight after spreading.
The degradation reactions not only limit the life duration of the active ingredient but also lead to the formation of by-products.
The toxicity of these by-products is very often not known but, in any case, they accumulate in the plant and can enter the alimentary chain.
To overcome and to limit the degradation of phytosanitary products, EP 0252463 proposes to entrap the active ingredient, pesticide, in polymer lattices.
A formulation comprising an active ingredient in a microcapsule and a dye which protects the active component from degradation by UV-light is proposed in WO2006/077394.
US2003/186818 teaches the use of co-products, called “soapstock”, obtained in the manufacture of vegetable oils as a photo-protective agent for various applications including protection of herbicides and pesticides. The soapstock is acidulated by adding acid and the oil is recovered from the obtained acidified solution. However this oil penetrates inside the leaves leading to a loss of the photo-protective activity.
WO91/19417 teaches the use of yeast as a stabilizer for photosensitive insecticides, herbicides and insecticides and herbicide synergists. However in that case the active ingredient is no longer bio-available.
WO2005/072680 proposes to coat a horticultural active compound with a surface of doped TiO2 and/or ZnO in order to increase the shelf life of horticultural formulations. However the products have some toxicity.
K. M. S. SUDARAM and J. CURRY have proposed in “Effect of some UV light absorbers on the photostabilization of azadirachtin, neem-based biopesticide” published in Chemosphere, Vol 32, No 4, pp 649-659, 1996, formulations containing neem-based azadirachtin insecticides and UV absorbers, to photostabilize the insecticides. However, the photo-protective agent which is used can have some toxicity because it is a synthetic product.
YASSER EL-NAHHAL and al., propose in Applied Clay Science, 14, (1999) 105-119, organo-clay based formulations for rendering less volatile and to better protect from photodegradation commercially available emulsifiable concentrate formulations of alachlor and metolachlor. The UV absorbers are synthetic UV absorbers so that they can have some toxicity. Moreover the active ingredient is no longer bio-available.
YOUBIN SI and al., in Chemosphere 54 (2004) 943-950, have proposed photostable formulations of the herbicide bensulfuron-methyl. The formulations have been obtained by absorbing the herbicides on clays or on clays pre-adsorbed with the organic cation malachite green. As a consequence, the herbicides are no longer bio-available.
BLANCA CASAL and al., have proposed, in Applied Clay Science 18 (20014) 245-254, sepiolite-based materials for the photo- and thermal-stabilization of pesticides. Once again, in this case, the pesticides are no longer bio-available.